Display panel or portion thereof with a transitional graphical user interface



FIG. 1 is a front view of a display panel or portion thereof with a transitional graphical user interface showing a first image in a sequence of our design;

FIG. 2 is a front view of a second image in the sequence;

FIG. 3 is a front view of a third image in the sequence;

FIG. 4 is a front view of a fourth image in the sequence; and,

FIG. 5 is a front view of a fifth image in the sequence.

The appearance of the image in each embodiment sequentially transitions between the images shown in FIGS. 1 through 5. The process or period in which one image transitions into another forms no part of the claimed design.

The outermost broken line rectangle illustrates a display panel or portion thereof that forms no part of the claimed design. The remaining broken lines, including all text, illustrate portions of the graphical user interface and form no part of the claimed design. 

CLAIM The ornamental design for a display panel or portion thereof with a transitional graphical user interface, as shown and described. 